The resurgence of the rigid front fork in recent years is quite interesting. I can recall from my past mountain biking experience the fall from grace that the rigid fork took in the early 90's. Now it would seem that the rigid fork is back, and it's not going away any time real soon.
The early 90's were a time of mass change in the mountain biking world. If somebody asked you, "What's new in mountain bikes this year?", it was a question you couldn't answer in an hour of yakking. One of the major upheavals was the battle between suspended forks and rigid forks. It didn't take long before you weren't cool if you weren't sporting some sort of "front boinger". Frame geometry changed to accomodate these new forks, and even things like head sets, and tires were affected in one way or another. Soon, even the manufacturers quit offering nice rigid forks. Only the entry level models had any sort of rigid fork by the end of the decade.
Now you see several rigid forks for both 26 and 29 inch wheels available. Nice forks with True Temper, Reynolds, and even carbon fiber fork blades. So, what's the deal? Why the return to the rigid fork? I think it has to do with several things.
Tires: Back in the day, rigid forks roamed freely on the face of the earth. A symbiotic relationship between the rigid fork and really fat tires was in effect that caused a benefit to trail riders. Big tires were "suspension", and rigid forks were compliant, yet laterally stiff. Then when suspension came and caused the rigid fork to become extinct, there was no real need for big, wide rubber. Or so we thought. It took more speed and longer travel suspension to point out the need for bigger, meatier tires to handle the performance needs of the "free ride" crowd. Oddly enough, someone remembered that the fat tires worked well on rigid forks, and the market for nice rigid forks became alive again.
Single Speeders: Ah yes! The simple life embodied by the purety of the single speed experience! No need for a "high maintenance" item like a front suspension fork! Single speeders mindset and culture also pointed to a potential for the revival of the rigid fork.
29"ers: The big wheel that smoothed out the trail was much like the fatty front tire for 26"ers. Single speeders took to 29"ers like white on rice because of the momentum holding qualities plus the aforementioned trail smoothing attributes. Finally, suspension for 29"ers didn't exist for most of the world at first! You pretty much had to ride rigid! This in itself showed alot of folks that perhaps they didn't need or want a front suspension fork. It also prompted alot of custom builders to start producing long legged steel forks to accomodate the new wheel format. Alot cheaper and easier than making your own front suspender!
Now you can find rigid forked mtb bikes popping up in shops again. While the rigid fork will never be as popular as it was in days gone by, I believe it's back, and it's here to stay.